1. Field of the Invention
This invention relates to the field of model trains. More specifically, the invention comprises a system for creating externally generated sound effects which are synchronized with the motion of a model train.
2. Description of the Related Art
Hobbyists and serious collectors have enjoyed model trains for many decades. The high end of this marketplace places a premium on realism. The models are highly detailed and historically accurate. They may include inertia-simulating motion control, realistic sound effects, and smoke effects. The customer generally desires a model train which behaves as closely as possible to its full-sized counterpart.
Numerous inventions have added to the realism of model trains. U.S. Pat. No. 6,765,356 to Denen, Young, Moreau, Pierson, and Grubba (2004) provides a good explanation of motor control, motor position sensing, motor speed sensing, and sound effects. U.S. Pat. No. 6,765,356 is hereby incorporated by reference.
U.S. Pat. No. 6,485,347 to Grubba and Morrison (2002) provides a good explanation of smoke generating hardware and control techniques. U.S. Pat. No. 6,485,347 is also incorporated herein by reference.
U.S. Reissue Pat. No. RE38,660 to Novosel, Boles, and Fleszewski (2004) provides a good explanation of digital sound processing using a microprocessor and memory means which travel along with the model train. That patent describes the use of a small speaker contained within a model locomotive to generate the sounds. U.S. Pat. No. RE38,660 is therefore also incorporated by reference.
This disclosure uses the term “train sounds” to generally describe the sounds emitted by an actual train in operation. These would include hissing steam, squealing brakes, “chuffing” steam pistons, and the rumble of a large diesel engine. Those skilled in the art will know that most model trains are fairly compact. The inherent size limitation has traditionally limited the realism of the sound produced by a model train, since only a small speaker will fit in the available space. Actual trains are, of course, massive. They produce many low-frequency sounds having substantial amplitude. A system capable of reproducing the full spectrum of actual train noises would therefore be more realistic.